17.If the 36[Assessing] Officer or the Commissioner (Appeals) in the course of any proceedings under this Act is satisfied that any person has concealed particulars of chargeable expenditure or has furnished inaccurate particulars of such chargeable expendi­ture, he may direct that such person shall pay by way of penalty, in addition to any expenditure-tax payable by him, a sum which shall not be less than, but which shall not exceed twice, the amount of tax sought to be evaded by reason of concealment of particulars of chargeable expenditure or the furnishing of inac­curate particulars of such chargeable expenditure :

Provided that if the amount of chargeable expenditure (as deter­mined by the 36[Assessing] Officer on assessment) in respect of which particulars have been concealed or inaccurate particulars have been furnished exceeds a sum of twenty-five thousand rupees, the 36[Assessing] Officer shall not issue any direction for payment by way of penalty without the previous approval of the 37[Additional Commissioner or, as the case may be, of the] 38[Deputy] Commissioner.